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A001685 a(0) = 1, a(1) = 2, a(2) = 3; for n >= 3, a(n) = a(n-2) + a(n-1)*prod_{i=1..n-3} a(i).
(Formerly M0740 N0278)
8
1, 2, 3, 5, 13, 83, 2503, 976253, 31601312113, 2560404986164794683, 202523113189037952478722304798003, 506227391211661106785411233681995783881012463859772443053 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

From a continued fraction.

Every term is relatively prime to all others. - Michael Somos Feb 01 2004

REFERENCES

V. C. Harris, Another proof of the infinitude of primes, Amer. Math. Monthly, 63 (1956), 711.

R. Mestrovic, Euclid's theorem on the infinitude of primes: a historical survey of its proofs (300 BC--2012) and another new proof, Arxiv preprint arXiv:1202.3670, 2012 - From N. J. A. Sloane, Jun 13 2012

N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

LINKS

Table of n, a(n) for n=0..11.

PROG

(PARI) a(n)=if(n<3, max(0, n+1), a(n-2)+a(n-1)*prod(i=1, n-3, a(i))) - Michael Somos Feb 01 2004

CROSSREFS

Cf. A003686, A064526.

Sequence in context: A042695 A074394 A056162 * A074691 A139589 A152114

Adjacent sequences:  A001682 A001683 A001684 * A001686 A001687 A001688

KEYWORD

nonn

AUTHOR

N. J. A. Sloane.

EXTENSIONS

Edited by N. J. A. Sloane, Jun 12 2006

STATUS

approved

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Last modified June 17 23:56 EDT 2013. Contains 226327 sequences.